never seen anything like thatOften used with никогда or давно. Depending on context, it can express surprise or strong disapproval, as in «И чтобы я больше такого не видел!» — “And don't let me see that again!” The form changes with the noun or person referred to: такого, таких, такой.
RU: Я никогда такого не видел — это невероятно!
EN: I've never seen anything like that—it's incredible!